Sifter



H. BENJAMIN Oct. 11, 1955 SIFTER Filed Sept. 28, 1953 FIG. 2

HARRY BENJAMIN T R- United States Patent SIFTER Harry Benjamin, Cleveland, Ohio, assignor to The Harshaw Chemical Company, Cleveland, Ohio, a corporation of Ohio Application September 28, 1953, Serial No. 382,750

6 Claims. (Cl. 209-334) This invention relates to a sifter and more particularly to one which is especially adapted for use in laboratories for the handling of relatively small amounts of materials.

It is an object of the invention to provide a simple and effective electromagnetically operated sifter including means for agitating a relatively small sifter and especially for imparting to such sifter a rapid vibratory motion in a horizontal plane. A further object is to provide a device which will at the same time impart to such sifter a vibratory motion in a horizontal plane and rotation about a vertical axis. Other and more limited objects will become apparent from the following description when read in connection with the accompanying drawings.'

Fig. l is an elevation of a device embodying my invention.

Fig. 2 is a top plan view of the device illustrated in Fig. 1.

Referring now to the drawings, the numeral 10 indicates a base which preferably is composed of heavy material, such as lead, adapted to give substantial stability to the device. Mounted on the base 10 is a housing 11 which may be composed of sheet metal such as copper, brass, or aluminum and which may be provided with doors. 12 whereby the interior becomes available for storage of accessories such as sifters of different sizes, or the like. The housing 11 is provided, as shown, with a horizontal upper surface. Secured to such surface is a V-shaped element 13 which may be composed of brass or other nonmagnetic material and is secured to the upper surface of the housing 11 by welding or by flanges (not shown) riveted or bolted to such horizontal surface. Secured to the inner aspects of the V-shaped element 13 are yieldable coverings 14 and 15 which may be composed of rubber, cork, or other yieldable material.

Secured to the upper surface of the housing 11 in any suitable manner is an electromagnet 16 which is energized from an alternating current line 17. The line 17 may pass to a switch and rheostat 18 and thence by way of conductors 19 to a half-wave rectifier 20 from which current may be conducted through the conductor 21 to the electromagnet 16. While the device may be operated on alternating current of the 60 cycle or cycle variety (or at other frequency suitably from 20 to 100 cycles per second), it is preferred to pass such alternating current through a rectifier whereby half of each wave is blocked thereby supplying to the electromagnet an interrupted, unidirectional current. If desired, the rectifier 20 may be designed to include a switch whereby it may be bypassed, allowing the passage of alternating current to the electromagnet 16.

The sifter, comprising a lower portion 22 preferably composed at least in part of iron or other magnetic material and an upper portion 23 which may or may not be composed partly or wholly of iron or other magnetic material is adapted to be supported by the upper surface of the housing 11 and to be received between the yieldable stop elements 14 and 15 and to be vibrated in that position in a horizontal plane by the variable attraction of the electromagnet 16. The upper portion 23 of the sifter has a sieve in the bottom and is removably attached to the lower portion 22 which is a receiver for the finer material passing through the sieve. If desired the upper portion 23 of the sifter may be provided with a cover to exclude foreign material. It will be understood, of course, that the portions of the sifter which are composed of iron or steel or other magnetic material may be suitably plated for protection against corrosion with any desired metal, suitably nickel and chromium. It may also be provided with an organic coating if desired either in substitution for the metallic coating or in addition thereto. The base 10 may be composed of cast iron if it is sufliciently distant from the electromagnet 16 as not to materially affect its operation. Even the housing 11 may be composed of ferrous metal if thin enough that it does not interfere seriously with the action of the electromagnet.

In operation, the material which is to be separated into coarser and finer particles is placed in the upper portion 23 of the sifter, the receiving portion 22 having been attached and simply placed upon the upper surface of the housing 11 in the opening between the yieldable stops l4 and 15 and the current turned on. The electromagnet alternately pulls the sifter into close engagement with the yieldable stops and releases it, permitting the resiliency of the stops to move it slightly away from the magnet again. This results in a rapid horizontal vibration of the sifter and also a slower rotatory motion thereof. Thus, the sifter, which may be somewhat variable as to size after being supplied with the sample, is placed. in position and allowed to remain for such a period of time as necessary to complete the separation. If desired, a timing mechanism may be incorporated in the circuit whereby to attract the attention of the operator when a sufiicient time has elapsed by means of a suitable alarm and if desired the current can be turned off at the same time. The yieldable coverings 14 and 15 may be omitted. and a yieldable covering or belt placed on the outer surface of the sifter. Such a structure would obviously be equivalent to that shown, except that it would somewhat increase the weight of the sifter. Accordingly, the structure shown is pre ferred. Also omitting the coverings 14 and 15 without any yieldable material being applied to the sifter the device may operate fairly well owing to the inherent resiliency of the V-shaped element 13.

From the foregoing, it will be seen that I have provided a device which is well adapted for its intended purpose and while I have shown and described the present preferred embodiment of the invention, I wish it understood that numerous variations are possible without departing from the essentials, and I therefor desire to be limited only in accordance with the appended claims.

Having thus described my invention, what I claim is:

1. In a device of the class described, means providing a substantially horizontal supporting surface, a pair of stops spaced above said surface, a substantially cylindrical sieve resting freely on said surface in contact with said stops and being mechanically unconnected with respect to said surface and said stops, an electromagnet positioned in fixed relation to said supporting surface with a pole adjacent one of said stops on the side thereof opposite the other of said stops and means for supplying to said electromagnet an energizing current of variable character with respect to time, said electromagnet being located at a position to urge said sieve into contact with said stops: upon energization, said sieve being composed at least in part of magnetic material and being of a size too large to pass between said stops, whereby such sieve may be caused to vibrate in a horizontal direction, said sieve comprising a substantially cylindrical receptacle having a screen spaced above the bottom thereof.

2. A device as defined in claim 1 wherein further said sieve is located above said surface with the centerof its core at approximately the horizontal level of a point of contact of said sieve with said stops.

3. In a device of the character described, a base having a substantially horizontal upper surface, a V-shaped. abutment extending upwardly from said surface and fixed with respect thereto, a substantially cylindrical sieve composed at least in part of magnetic material and being of an external diameter to engage against both legs of said abutment, an electromagnet so, located as to urge said sieve into contact with both said legs when energized and means for supplying said electromagnet with current of variable character with respect to time whereby to impart to said sieve a vibratory motion in a horizontal direction, said current being regularly variable and of frequency from 20 to 100 .cycles per second, said sieve being mechanically unconnected to said surface and said abutment and comprising a substantially cylindrical receptacle having a screen spaced above the bottom thereof.

4. In a device of the character described, a base having a substantially horizontal upper surface, a V-shaped abutment extending upwardly from said surface and fixed with respect thereto, a substantially cylindrical sieve composed at least in part of magnetic material and being of an external diameter to engage against both legs of said abutment, an electromagnet so located as to urge said sieve into contact with both said legs when energized and means for supplying said electromagnet with current of variable character with respect to time whereby to impart to said sieve a vibratory motion in a horizontal direction, said current being regularly variable and of frequency from 20 to 100 cycles per second, all portions of said device within close proximity to said surface being composed of substantially non-magnetic material except said sifter and the core of said electromagnet, said sieve being mechanically unconnected to said surface and said abutment and comprising a substantially cylindrical receptacle having a screen spaced above the bottom thereof.

5. In a device of the character described, a base having composed at least in part of magnetic material and being of an external diameter to engage against both said yieldable surface coverings, an electromagnet so located as to urge said sieve into contact with both said yieldable coverings when energized and means for supplying said electromagnet with current of variable character with respect to time whereby to impart to said sieve a vibratory motion in a horizontal direction, said current being regularly variable and all portions of said device within close proximity to said surface being composed of substantially non-magnetic material expect said sifter and the core of said electromagnet, said sieve being mechanically unconnected to said surface and said abutment and comprising a substantially cylindrical receptacle having a screen spaced above the bottom thereof.

6. In a device of the character described, a base having a substantially horizontal upper surface, a V-shaped abutment extending upwardly from said surface and fixed with respect thereto, yielding surface coverings on the inner aspect of said abutment, a substantially cylindrical sieve composed at least in part of magnetic material and being of an external diameter to engage against both said yield? able surface. coverings, an electromagnet so located as to urge said sieve into contact with both said yieldable coverings when energized and means for supplying said electromagnet with current of variable character with respect to time whereby to impart to said sieve a vibratory motion in a horizontal direction, said current being regularly variable and of frequency from 20 to 100 cycles per second, all portions of said device within close proximity to said surface being composed of substantially non-magnetic material except said sifter and the core of said electromagnet, said sieve being mechanically unconnected to said surface and said abutment and comprising a substantially cylindrical receptacle having a screen spaced above the bottom thereof.

a substantially horizontal upper surface, a V-shaped abutment extending upwardly from said surface and fixed with respect thereto, yieldable surface coverings on the inner aspect of said abutment, a substantially cylindrical sieve Snyder Dec. 17, 1946 Devol Mar. 15, 1949 

